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Date: Tue, 3 Feb 2026 09:56:30 +0100
Message-ID: <CAOWwgpnrnk-a6uczGnuE76rpd9mZvwXs=SHwuo+-4fWgLm9Jcg@mail.gmail.com>
Subject: Re: [PHP-DEV] [RFC] Allow Reassignment of Promoted Readonly
 Properties in Constructor
To: Rob Landers <rob@bottled.codes>
Cc: PHP Internals List <internals@lists.php.net>
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From: nicolas.grekas+php@gmail.com (Nicolas Grekas)

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Hi Rob,

Le mar. 3 f=C3=A9vr. 2026 =C3=A0 09:50, Rob Landers <rob@bottled.codes> a =
=C3=A9crit :

> On Mon, Feb 2, 2026, at 22:14, Nicolas Grekas wrote:
>
> Hi Marco,
>
> Le lun. 2 f=C3=A9vr. 2026 =C3=A0 11:54, Marco Pivetta <ocramius@gmail.com=
> a =C3=A9crit :
>
> Hey Nicolas,
>
>
> On Thu, 22 Jan 2026 at 16:34, Nicolas Grekas <nicolas.grekas+php@gmail.co=
m>
> wrote:
>
> Dear all,
>
> Here is a new RFC for you to consider:
> https://wiki.php.net/rfc/promoted_readonly_constructor_reassign
>
>
>
> What happens if one calls `$obj->__construct(1, 2, 3)` (on an already
> instantiated `$obj`) in the context of this patch?
>
>
> Thanks for asking, I didn't think about this. This made me also think
> about ReflectionClass::newInstanceWithoutConstructor().
> I clarified this in the RFC, see "Direct __construct() Calls Cannot Bypas=
s
> Readonly" and "Reflection: Objects Created Without Constructor".
> Patch and PR updated also if anyone wants to run some code where this RFC
> can be played with.
>
> Cheers,
> Nicolas
>
>
> Hi Nicolas,
>
> Under "Child Classes Can Reassign Parent Properties": this feels like a
> major footgun. Calling parent::__construct() won't allow a reset (per the
> rules of calling a constructor directly); which would completely break
> inheritance... but then in the examples it says that calling a constructo=
r
> directly can reset it -- but you can't?
>
> This feels really inconsistent to me.
>
> =E2=80=94 Rob
>

Yes, the text was ambiguous. The implementation allows
parent::__construct() during the initial construction (normal inheritance),
and only blocks explicit __construct() calls after construction completed.
I=E2=80=99ve clarified this in the RFC.

Nicolas

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<div dir=3D"ltr"><div dir=3D"ltr">Hi Rob,</div><br><div class=3D"gmail_quot=
e gmail_quote_container"><div dir=3D"ltr" class=3D"gmail_attr">Le=C2=A0mar.=
 3 f=C3=A9vr. 2026 =C3=A0=C2=A009:50, Rob Landers &lt;rob@bottled.codes&gt;=
 a =C3=A9crit=C2=A0:<br></div><blockquote class=3D"gmail_quote" style=3D"ma=
rgin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:=
1ex"><u></u><div><div>On Mon, Feb 2, 2026, at 22:14, Nicolas Grekas wrote:<=
/div><blockquote type=3D"cite" id=3D"m_6564486400604031585qt"><div dir=3D"l=
tr"><div dir=3D"ltr">Hi Marco,</div><div><br></div><div><div dir=3D"ltr">Le=
=C2=A0lun. 2 f=C3=A9vr. 2026 =C3=A0=C2=A011:54, Marco Pivetta &lt;<a href=
=3D"mailto:ocramius@gmail.com" target=3D"_blank">ocramius@gmail.com</a>&gt;=
 a =C3=A9crit=C2=A0:</div><blockquote style=3D"margin:0px 0px 0px 0.8ex;bor=
der-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"ltr"><div=
 dir=3D"ltr"><div>Hey Nicolas,</div><div><br></div></div><div><br></div><di=
v><div dir=3D"ltr">On Thu, 22 Jan 2026 at 16:34, Nicolas Grekas &lt;<a href=
=3D"mailto:nicolas.grekas%2Bphp@gmail.com" target=3D"_blank">nicolas.grekas=
+php@gmail.com</a>&gt; wrote:</div><blockquote style=3D"margin:0px 0px 0px =
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"=
ltr"><div>Dear all,</div><div><br></div><div>Here is a=C2=A0new RFC for you=
 to consider:</div><div><a href=3D"https://wiki.php.net/rfc/promoted_readon=
ly_constructor_reassign" target=3D"_blank">https://wiki.php.net/rfc/promote=
d_readonly_constructor_reassign</a></div></div></blockquote><div><br></div>=
<div><div><br></div><div>What happens if one calls `$obj-&gt;__construct(1,=
 2, 3)` (on an already instantiated `$obj`) in the context of this patch?</=
div></div></div></div></blockquote><div><br></div><div>Thanks for asking, I=
 didn&#39;t think about this. This made me also think about ReflectionClass=
::newInstanceWithoutConstructor().</div><div>I clarified this in the RFC, s=
ee &quot;Direct __construct() Calls Cannot Bypass Readonly&quot; and &quot;=
Reflection: Objects Created Without Constructor&quot;.</div><div>Patch and =
PR updated also if anyone wants to run some code where this RFC can be play=
ed with.</div><div><br></div><div>Cheers,</div><div>Nicolas</div></div></di=
v></blockquote><div><br></div><div>Hi Nicolas,</div><div><br></div><div>Und=
er &quot;Child Classes Can Reassign Parent Properties&quot;: this feels lik=
e a major footgun. Calling parent::__construct() won&#39;t allow a reset (p=
er the rules of calling a constructor directly); which would completely bre=
ak inheritance... but then in the examples it says that calling a construct=
or directly can reset it -- but you can&#39;t?</div><div><br></div><div>Thi=
s feels really inconsistent to me.</div><div><br></div><div id=3D"m_6564486=
400604031585sig121229152">=E2=80=94 Rob</div></div></blockquote><div><br></=
div><div>Yes, the text was ambiguous. The implementation allows parent::__c=
onstruct() during the initial construction (normal inheritance), and only b=
locks explicit __construct() calls after construction completed. I=E2=80=99=
ve clarified this in the RFC.</div><div><br></div><div>Nicolas</div></div><=
/div>

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